MapServer is an open source, map server for web applications. I have written a Tcl interface for Mapscript, MapServer's scripting interface. MapScript/Tcl is now a part of the MapServer 3.4 (beta) release. Get the 'nightly' CVS build from the MapServer pages while 3.4 is still in development.
MapServer Workbench is a suite of cooperative tools to build MapServer applications. The tools are written in Tcl/Tk, and use the Mapscript/Tcl interface.
GRASS (and here too) is an open source, geographical information system. Below are some tools that I have developed for GRASS. All software on this page is offered under the GNU Public License (GPL), the same as the rest of GRASS.
The HTMLMAP driver is now a part of Grass5.
s.to.poly.sh creates coarse-grained polygons around site data. It allows the site data to 'clump' into several smaller area, rather than trying to totally encompass all data.
Makes importing DEM data into a Lat-Lon database a piece of cake. The tedious part of finding the DEM's boundaries is totally automated.
This simply creates most of the sub-directories used in a mapset.
These three scripts create and manipulate a region stack. Handy when you want to temporarily create or switch to another region definition with g.region, but want to come back to your original one later.